Product development for industrial applications involves extensive research and preparation in an environment of rolling deadlines and ever-evolving product specifications. While time-to-market for this sector may not be as short as it is for consumer electronics, products must ship quickly and with as many essential functions, features and potential hooks for the next generation as possible. Companies vie to be industry leaders in their respective competitive arenas—especially in new markets such as green power, which in their infancy and without defined leaders require pioneers to design, develop and deliver new products. Success depends not only on an inspired, dedicated team of engineers, advanced computing technology and new materials, but also on angel investors or government agencies to provide grants for promising approaches to improved energy generation, distribution, monitoring, metering and consumption.

In the fall of 2011, engineers from Princeton Power Systems (PPS), a New Jersey-based manufacturer of advanced power-conversion products and alternative-energy systems, demonstrated their latest green power product. This demand response inverter (DRI) was the result of a three-year collaboration between PPS, the United States Department of Energy and Sandia National Laboratories’ Solar Energy Grid Integration Systems (SEGIS).

The resulting multi-terminal DRI (Figure 1) is uniquely flexible to be more reliable, more efficient and more cost-effective than currently available inverters. Equipped with multiple AC and DC terminals, the DRI can route power to the grid, a microgrid, DC energy storage or dynamic loads. Programmable power curves and charge profiles enhance control for generators, loads and batteries, ensuring greater efficiency. And the use of advanced high-capacity long-lifespan switches maximizes reliability.

Princeton Power Systems showcased features of the DRI that improve electrical-grid interconnectivity and efficiency, enhance the performance of renewable energy systems and allow for better integration of electric vehicles and distributed power generation. The DRI was part of the company’s “An Island in the Sun” microgrid demonstration (Figure 2), which detailed key advancements in clean technology and manufacturing, including a 200-kilowatt solar array and lithium-ion battery system.

A microgrid can operate independently of a major utility grid to supply reliable, low-carbon-emission energy. PPS’ DRI is compatible with AC generators such as diesel or gas, and with photovoltaic (PV) or wind inputs. A small community using a DRI is less dependent on the grid and can reduce its carbon footprint and utility costs. The DRI can also provide grid services, PV with storage and charging for electric vehicles.